The film industry, that well-spring of cynicism, is not the most obvious place to go looking for salvation. But Walter Salles, director of the much feted Central Station and an emblematic figure within the Brazilian film industry, is an optimistic man.

'What we all look for is the possibility to rewrite in one way or another our own story,' says Salles, speaking from his Videofilmes studio in Rio de Janeiro. You hope his words of new beginnings might be true about life. They are certainly true of Brazil's film industry, triumphantly back on the world scene after a long hiatus.

There's a hot rash of Brazilian films screening across London in various festivals over the coming months. In this veritable cine-carneval Salles's work will be among films testifying to the power and breadth of what has been shot in Brazil - most of which has been cruelly denied to audiences in this country. Love stories of the wealthy, like Baretto's seductive Ipanema-set Bossa Nova , or of the poor, like veteran director Carlos Diegues's tragic Orfeu , will be shown alongside tense tales of the southern badlands, like Beto Brant's acclaimed debut Belly Up . There are takes on what it means to be black (Macunaima), or of Japanese (Gaijin) or Italian (O Quadrilho) origin in perhaps the world's most successful melting pot. And also a generous helping from the Cinema Novo of the 1960s, when Brazilian directors kept pace with Italian neo-realists like Fellini.

This month sees the National Film Theatre showing 24 Brazilian films while the Barbican runs another dozen, all from the 1990s. Then, in September, the indefatigable Eva Tarr will launch her 11th annual Latin American Film Festival, first at her Metro cinema in W1 then around the UK, again with a focus on Brazil. 'You leave a Brazilian film feeling alive,' says Tarr.

Away from the screen, an unprecedented wave of Brazilian rhythms, photography, theatre and dance will also serve as background throughout the summer. The excuse is the country's 500th birthday, which has seen big Brazilian companies overjoyed to score PR points by sponsoring international cultural tours. Back in South America's largest country, some of the reflection is darker, focusing on a society that produces the world's largest gap between rich and poor and enough real-life violence that no local director feels the urge to glamorise it as Western gangster chic.

But while their country's enormous problems are treated with unfailing realism, Brazilian films do emanate a steady faith in the prospect of redemption. Salles sees it as the idealism of youth in a nation still preoccupied with discovering its identity: 'How can you be cynical in a moment like this?'

And he sees film as a means to change things, even though 'the targets are not so easily identifiable' as they were in the clear-cut military dictatorship years of the 1970s and 80s. 'The day I start to believe that there are no inter-relations between art and society, I will stop making films,' he declares.

Salles is not alone. Brazilian films, whatever their overt theme, do tend to focus on changing the way people see each other. John King, author of a forthcoming book on Latin American cinema, Magical Reels, and one of the organisers of the NFT series, points out how the focus has shifted from the overtly political message of Cinema Novo to a more psychological and complex approach today. Yet still most films from Brazil are moral fables, saccharine-free.

Here in Britain the idea of moral progress through film (especially subtitled ones!) sounds fatally worthy, and dull to watch, especially to the distributors and TV execs who control what is on offer to us on any given evening. They have proved that Hollywood, celebrities, a steady ratcheting-up of violence and only the most pre-tested plot formulas can be converted into steady cash.

Yet history shows audience tastes are mobile, while many people do seem to want something more from their movies. And the thing about most of these current Brazilian directors is that they do have a way with cinema: a 'way' in that even though budgets are small and subtitles do need reading, your emotional engagement is turned on like a switch and then held. Inventive disrespect for genres is combined with characterisations and narratives that pull you in. The likes of Barreto, Salles and Lima make it all seem so easy on the screen, just as Pelé did on the football field. Film is a serious business to Brazilians - and they are seriously good at it.

The directors are helped by strong, occasionally breathtaking, cinematography - witness the work of Affonso Beatto in Orfeu or Pedro Farkas in the haunting Oyster and the Wind , unfortunately absent from the Barbican series. A lot of Brazilian camerawork is influenced by years when their film industry hibernated and wages were earned, just as by our own Ridley Scott, in advertising. This overlap is still alive - Salles's own studio still earns some handy money that way.

It's with these companion qualities that intelligent cinema becomes a pleasure. That sense of leaving the cinema feeling quite different about something, even if it takes a few days to define what, can happen easily with good Brazilian films (though with Helena Solberg's biopic Carmen Miranda - Bananas is my Business I think you just need to love samba and fruit-topped hats). In this they share something with current output from China and Iran, but perhaps a narrower cultural gulf means less is lost to European viewers in translation.

But where does this faith come from? The 'young country' argument doesn't fully convince. US culture is more youthful, yet most Hollywood pictures are cynical in how they treat their audiences. Perhaps a more likely reason is the innate religiosity of Brazilian culture, whether those roots are Amerindian, African, Catholic or (as with several directors) Jewish. Belief just seems to make more sense in Brazil, whether you are between the Sugar Loaf mountain and Atlantic breakers or on the edge of the world's last major rainforest.

Some sort of providence did seem to guide the making of Central Station . Salles says: 'We looked for the boy who could play Josué's role for a whole year, and interviewed over 1,500 children.' Yet Vinicius de Oliveira, the nine-year-old actor whose relationship with Fernanda Montenegro is the backbone of the film, found Salles. Vinicius was shining shoes at the airport and was guided to Salles's footwear as a likely prospect. 'He chose me before I could choose him.'

Even before Central Station , the 'second chance' theme was prominent in Salles's oeuvre. In Socorro Nobre he presents the true story of how a 36-year term female prisoner began a relationship with a Polish-Jewish sculptor who carves wood he finds in the Amazonian jungle (giving those branches their own second chance in life). In the suspenseful Midnight a prisoner is allowed to escape on millennium eve on condition he carry out a murder. Most famously, the Oscar-nominated and magical Central Station gave us Montenegro at her best as the epitome of a cynical character given an opportunity for self-reform.

Brazilian cinema itself is going through a rebirth. After the international success and optimism of Cinema Novo came deep pessimism as military rule was followed by a free-market president so corrupt he was impeached. Film production dried up to almost nothing: in 1992 just 36,000 tickets were sold within Brazil to watch domestic pictures. Now 25 titles are made each year and there was a home audience of six million for Brazilian-made films in 1999.

The new films are pulling in both international awards and foreign actors, like Alan Arkin in Four Days in September and Amy Irving in Bossa Nova.

The revival is also a broader one. The traditional film production centres of Rio and Sao Paulo have been joined by new production companies in cities of greater African influence, such as Fortaleza, and in mountainous Minas Gerais. City governments have often been catalysts, offering tax breaks and that uniquely Brazilian way of helping overcome problems known as jeito .

Salles, sitting astride a stack of Golden Globes, Baftas and plaudits from Berlin and Cannes (50 awards for Central Station alone), is surely the patron saint of this renaissance. Helpfully, given his spokesman role, he is as articulate in French and English as in Portuguese; the man is friendly, generous, funny and on top has to suffer film-star good looks.

But like all supposed saints, underneath he is human. A privileged background and a period working in the advertising game might both charge his progressive role now with the impetus of guilt (though perhaps that itself brings more understanding of the human condition).

So good luck to the plucky, crusading Brazilians and the films they are bringing us. Here, under grey clouds, and armed with consummate skill at put-downs and indifference, we Brits may prove too tough a quarry for redemptive cinema. This summer offers a chance to find out.

World cinema's other recent hotspots

Denmark

The reasoning behind the Dogme 95 group's back-to-basics manifesto was debatable but it produced a flurry of impressive movies including Festen and Mifune from last year. However, it seems leading light Lars von Trier has renounced the group's ethos with his new musical, Dancer in the Dark .

Iran

Despite artistic restrictions imposed by the autocratic regime, Iranian cinema has recently enjoyed a boom period. Directors such as Abbas Kiarostami (Taste of Cherry), Mohsen Makhmalbaf (Bread and Flower) and his daughter Samira Makhmalbaf The Apple), who made her debut as a teenager, have led the advance.

Hong Kong

The universal appeal of so-called chop-socky movies propelled Hong Kong martial arts movies into cult viewing internationally and influenced Hollywood. The likes of filmmaker John Woo (Bullet in the Head) and actors Chow Yun-Fat, Jackie Chan and Michelle Yeoh have subsequently had success in America.

China

According to Martin Scorsese, Chinese films were at the forefront of world cinema in the Nineties. Wary of the censors, the stirring films of directors such as Zhang Yimou and Chen Kaige used star Gong Li (Farewell My Concubine) and historical settings to critique contemporary society.